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Re: Parabolic - Why Spherical and not flat curve?

Subject: Re: Parabolic - Why Spherical and not flat curve?
From: "Fred Rowley" frowley
Date: Sat Dec 20, 2008 4:53 pm ((PST))
John,
I'm a little late posting to this -- just now found it. I built a
parabolic dish from the plastic material used for campaign signs --
routing the wedges from a pattern I got and adjusted off the web. The
material is corrugated -- enabling you to curve the wedge so long as
it's oriented at 90 degrees to the corrugation. I taped the wedges
together with aluminum tape into a pretty fair parabolic dish at
around 20" in diameter. It's light-weight and works pretty well
for recording birds. I don't have a Telinga to compare it with, but it
nevertheless is very directional -- the Longbilled Dowitchers
recording (under members/pnw) was made with this rig. That was about
my first ever recording, but I've used it a lot since. I can't afford
a mic, so I bolted my PCM-D50 into the dish. Hardly the best
arrangement, but keeps me happy for now.

fred


--- In  "John Tudor" <> wrote:
>
> Why do parabolic mics have to be spherical in shape.
>
> Would a flat plate, pulled into a paraboloid shape be as effective?
>
> It's a question I've had on my mind for some time and only actually
> thought to pose it here.
>
> Any opinions???
>
> Regards
> John
>








"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause


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